Clays of Yellowstone National Park

Abstract

The beauty and lure of Yellowstone National Park (YNP) to visitors from all around the world, in large part, comes from one of the very things that gives it its own name; The bright and colorful clay-sized mineral assemblage that make up its grand mountains, alluring valleys and brilliant hot springs. Proximity of The Clay Minerals Society (CMS) 2009 annual meeting to one of the largest terrestrial geothermal area in the world was ample reason to run the first “inquiry-based” CMS Workshop Lectures series (WLS), where both lectures and field excursions were emphasized. Inquiry teaching is investigating with questions, emphasizing evidence, forming explanations, making connections to the larger scientific community, and communicating conclusions. This accompanying volume brings another first to the CMS-WLS, which is electronic formatting and the benefit of color graphics, where a picture is worth a 1000 words. This volume includes displays and maps designed to bring the reader closer to YNP and perhaps let them better virtually sense the heat of hot springs, the smell of fumaroles, the sounds of gushing geysers, and the panorama of colors. This CMS-WLS also joins the mainstream realization that most Earth surface mineralization processes are mediated in the presence of biological communities. In fact, it may be harder to find an exception than a rule to this understanding. Microbiological metabolic pathways that exchange protons, electrons, and essential ions in nature are inextricably linked to clay sized mineral reaction pathways that do the same. For example, the reduction of iron in a smectite-bearing hot spring may be linked to the oxidation of N in a microbe (and visa versa). To understand the patterns that shape the clays and clay minerals we see today in YNP, one must embrace both the caldera-scale range of igneous, glacial, and hydrological processes, as well as the atomic-scale processes that occur along steep redox, pH, anions, cations, and temperature gradients. To this end, this CMS-WLS volume is holistically designed to cover (1) broad scale features of YNP as seen by remote sensing technology, (2) the evidence and processes by which biomineralization of clay sized materials occurs within terrestrial hot springs, and (3) the importance of spring chemistry, microbial communities, and other coexisting clay-sized, but non-clay mineral phases that are present. These perspectives lead to better understanding of the occurrences and variations of clay mineral assemblages existing within the environs of YNP and perhaps their analogs on early Earth and other planets.